P0116 on Toyota: How to Diagnose & Fix
Engine Coolant Temperature Sensor 1 Circuit Range/Performance
1 Toyota model · 1 documented issue · $100-$2,000 repair
P0116 on Toyota by model: symptoms, diagnosis and fix
The 2023+ Sequoia with the i-FORCE MAX twin-turbo V6 hybrid powertrain has experienced cooling system issues related to the added complexity of cooling both the twin-turbo engine and hybrid battery system. Owners report coolant loss with no visible external leak (internal leak at turbo coolant lines), electric cooling fan running continuously at high speed even in mild weather, and occasional overheating warnings during towing. The hybrid battery cooling circuit is separate from the engine cooling circuit and has its own failure modes.
Common Symptoms
- Coolant level dropping with no visible leak
- Cooling fans running at high speed constantly
- Overheating warning while towing
- Sweet coolant smell from engine bay
- Hybrid system reduced power warning
- Engine temperature gauge reading higher than normal
How to Fix
For coolant loss: have the dealer pressure test both the engine and turbo cooling circuits. Common leak points are the turbo coolant feed/return lines and the intercooler. For continuous fan operation: the hybrid battery cooling fans have an independent control module — check for DTCs related to battery temperature management. For towing overheating: ensure the transmission cooler and auxiliary cooler (if equipped with tow package) are functioning. Toyota has issued TSBs addressing cooling system software calibration. Verify all cooling system software is at the latest version.
Owner tips & cautions
- WarningCheck coolant level weekly during the first year of ownership. The twin-turbo system has many more coolant connections than a naturally aspirated engine. Catching a small leak early prevents overheating damage.
P0116 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0116 mean on a Toyota?
P0116 stands for "Engine Coolant Temperature Sensor 1 Circuit Range/Performance." P0116 means the engine control module detected an engine coolant temperature (ECT) sensor reading that is within wiring limits but doesn't make sense — for example, it doesn't rise as the engine warms up, or it disagrees with other temperature data. The ECT sensor reports coolant temperature, which the computer uses for fuel mixture, ignition timing, cooling-fan control, and emissions monitors. An implausible reading can cause poor fuel economy, hard cold starts, or failed emissions readiness. It is generally drivable but should be fixed for proper engine management. On Toyota it is documented across 1 model: Sequoia.
What are the most common causes of P0116?
The most common causes of P0116 are: Faulty or drifting engine coolant temperature sensor, Stuck-open thermostat (engine never reaches normal temp), Low coolant level or air in the cooling system, Wiring or connector resistance affecting the signal, Sensor reading inconsistent with intake-air temperature at cold start, Corroded sensor connector, PCM fault (less common). The specific cause varies by vehicle.
How much does it cost to fix P0116 on a Toyota?
Published repair estimates on Toyota range from $100 to $2,000 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0116 on a different make?
View P0116 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.